What is it? A technology built into the lining of Reebok's Crossfit U-Form models which, when activated by heat, softens and molds to the wearer's foot. The result is a custom fit ideal for the multitude of workouts in any regimen.

How does it work? First, the shoes are heated (in the oven for the U-Form Lifter model and with a hairdryer for the Nano U-Form) until the sneaker's U-Form tab turns red. Then, the wearer is instructed to lace the shoes up as normal and wear them seated for eight minutes, until the U-Form tab turns to a black color. Then, it's recommended that the sneakers are left to cool for around an hour before wear. The result is a form-fitting feel that will help you tackle Workouts of the Day more efficiently.

Notable products: Crossfit Nano U-Form, Crossfit U-Form Lifter

Bottom line: While heating your sneakers up before use may seem unconventional, it's hard to top the custom fit offered by Reebok U-Form.